AdjacentSpec BigDecimal test case failing on recent Scala 2.13 nightlies

[SethTisue]

this came up in the Scala 2.13 community build. after scala/community-build@54060a2 , refined started failing with:

the problem is reproducible outside dbuild just with ++2.13.1-bin-c5eed1d (after adding a resolver) followed by coreJVM/Test/compile

looking at git log --merges 63f89ba..c5eed1d, it seems likely the cause is scala/scala#8072

@lrytz @fthomas does this seem like a progression to you, and not a regression?

in the community build, I can work around it by temporarily excluding AdjacentSpec.scala

[lrytz]

Since somehow the message got lost above, it's

Expected: "could not find implicit value..."
Actual: No implicit Ordering defined for BigDecimal.

We have trait Adjacent[T] extends Ordering[T].

It is a bit confusing to see that message because implicitly[Ordering[BigDecimal]] exists.

We could include the type that is actually required in the message. Maybe also emit a warning when compiling Adjacent to suggest adding an @implicitNotFound? cc @som-snytt

[som-snytt]

The Scala PR moves the parent annotation text to the end of the message, so that the test just works again after the fix. It tests a prefix of the message.